The present invention relates to a system for protecting automotive exhaust gas combustion devices, and is conveniently, though not exclusively, applicable to engines with two sets of cylinders, each featuring an electronic fuel injection system. The system according to the present invention is of the type comprising an electronic control system whereby a central processing unit receives information signals from sensor means for detecting major operating parameters, such as engine speed, the engine air intake throttle setting and actual air intake by the engine, and whereby said control system controls fuel injection by means of specific injectors for each cylinder.
Known exhaust gas combustion devices are located inside the exhaust pipe, and comprise catalyzing elements for oxidizing substantially all the major unburnt pollutant gases. Said oxidizing process involves the production of heat, the amount of heat produced by the combustion devices being proportional to the amount of unburnt gases involved, which in turn depends on the operating, and particularly the ignition, characteristics of the engine. In the event of malfunctioning of the engine, particularly due to non-ignition of the fuel mixture, the temperature of the catalyzing elements may easily reach as high as 1000.degree. C., resulting in serious damage and, in view of the high cost of the elements themselves, considerable replacement costs.
Known warning devices for informing the driver of temperatures nearing said critical range fail to provide for effectively protecting the catalyzing elements, due to drivers often failing to adopt appropriate emergency measures.